[libcxx-commits] [libcxx] [libc++] Implement `ranges::fold_left_first` and `ranges::fold_left_first_with_iter` (PR #180214)

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c8ef wrote:

I opened this new PR to fix the conflicts and reduce the commit noise from the previous version. I have applied the new changes and resolved most of the feedback.

https://github.com/llvm/llvm-project/pull/180214